<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item,index) in levelList" :key="item.path">
        <span v-if="item.redirect==='noRedirect'||index==levelList.length-1" class="no-redirect">{{ item.meta.currentTitle || item.meta.title }}</span>
        <!-- <span v-else>{{ item.meta.title }}</span> -->
        <a v-else @click.prevent="resolvePath(item)">{{ item.meta.currentTitle || item.meta.title }}</a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script>
import pathToRegexp from 'path-to-regexp'
import { isExternal } from '@/utils/validate'
export default {
  data() {
    return {
      levelList: null
    }
  },
  watch: {
    $route(route) {
      // if you go to the redirect page, do not update the breadcrumbs
      if (route.path.startsWith('/redirect/')) {
        return
      }
      this.getBreadcrumb()
    }
  },
  created() {
    this.getBreadcrumb()
  },
  methods: {
    getBreadcrumb() {
      // only show routes with meta.title
      let matched = this.$route.matched.filter(
        (item) => item.meta && item.meta.title
      )
      const first = matched[0]

      if (!this.isDashboard(first)) {
        // matched = [{ path: '/dashboard', meta: { title: 'Dashboard' }}].concat(matched)
        matched = [].concat(matched)
      }
      this.levelList = matched.filter(
        (item) => item.meta && item.meta.title && item.meta.breadcrumb !== false
      )
    },
    isDashboard(route) {
      const name = route && route.name
      if (!name) {
        return false
      }
      return name.trim().toLocaleLowerCase() === 'Dashboard'.toLocaleLowerCase()
    },
    pathCompile(path) {
      // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
      const { params } = this.$route
      var toPath = pathToRegexp.compile(path)
      return toPath(params)
    },
    handleLink(item) {
      const { redirect, path } = item
      if (redirect) {
        this.$router.push(redirect)
        return
      }
      this.$router.push(this.pathCompile(path))
    },
    resolvePath(item) {
      if (!item.parent) {
        item = this.$store.state.sidebarsub.current
      } else {
        // 找出对应的 路由配置
        item = this.$store.state.sidebarsub.current.children.find(e => e.path === item.path)
      }
      let path = ''

      // 如果是个完成的url直接返回
      if (isExternal(item.path)) {
        path = item.path
      }
      // 如果是首页，就返回重定向路由
      if (item.path === '/') {
        path = item.redirect
      }

      // 如果有子项，默认跳转第一个子项路由
      /**
       * item 路由子项
       * parent 路由父项
       */
      const getDefaultPath = (item, parent) => {
        // 如果path是个外部链接（不建议），直接返回链接，存在个问题：如果是外部链接点击跳转后当前页内容还是上一个路由内容
        if (isExternal(item.path)) {
          path = item.path
          return
        }
        // 第一次需要父项路由拼接，所以只是第一个传parent
        path = item.path
        // 如果还有子项，继续递归
        if (item.children) {
          getDefaultPath(item.children[0])
        }
      }

      if (item.children) {
        getDefaultPath(item.children[0], item)
      }

      this.$router.push({ path })
    }
  }
}
</script>

<style lang="scss" scoped>
.app-breadcrumb.el-breadcrumb {
  display: inline-block;
  font-size: 14px;
  line-height: 50px;
  margin-left: 14px;

  .no-redirect {
    color: #97a8be;
    cursor: text;
  }
}
</style>
